* Kwon returns after quitting over quality issues
* No.2 design executive resigns for "personal reasons"
* Hyundai chairman known for abruptly sacking, rehiring (Add expert comments, background)
By Hyunjoo Jin
SEOUL, Feb 24 (Reuters) - South Korea's Hyundai Motor Co reinstated former research and development president Kwon Moon-sik on Monday only three months after he quit, the latest sudden management change at a carmaker battling to improve its reputation with customers.
Hyundai Motor also said Oh Suk-geun, head of its design center, had resigned for "personal reasons".
Group chairman Chung Mong-koo, a son of Hyundai's founder, has been known for abruptly firing executives and rehiring some of them.
"Chung's management style is good in that it injects tension into the organization. But it leads to a lack of consistency and transparency at the global company," said Lee Hang-koo, a senior researcher at state-funded Korea Institute for Industrial Economics & Trade.
Monday's surprise move comes as Hyundai, the world's fifth-biggest automaker along with affiliate Kia Motors , is preparing to unveil the fully revamped version of its key model, the Sonata, in South Korea next month, followed by the United States and other markets.
It also follows massive vehicle recalls in South Korea, the United States and other countries last year, as well as consumer complaints over quality issues at home, which have undermined the hard-earned reputation of a company that had worked hard to shed its image as a maker of shoddy cars.
Hyundai was among the bottom five scoring brands in the J.D. Power U.S. vehicle dependability survey released this month.
Hyundai said in a statement: "Given his expertise, experience and leadership skills, we reinstated president Kwon to enhance quality and R&D capability from scratch."
In November, Hyundai Motor, which has joint R&D operations with Kia Motors, said Kwon and two other R&D executives resigned over a slew of quality problems.
Kwon, who formerly served as chief executive at Hyundai's two auto electronics units, was known as being one of the top aides to Chung's only son and heir apparent Chung Eui-sun, media reports have said.
Kwon reports to R&D vice chairman Yang Woong-chul.
Kim Hae-jin, who had took over from Kwon in December, returned to his previous post overseeing power-train development.
Meanwhile, exterior design head Lee Byung-seob was appointed to take over Oh's position and will report to Peter Schreyer, who was named last year to oversee both Kia and Hyundai designs.
Hyundai and Kia's U.S. units also saw the departure of some of their top executives in recent months, after they suffered from lackluster sales in the key market. Kia's U.S. sales chief Tom Loveless recently left the company, while Hyundai said in December that its U.S. chief, John Krafcik, had stepped down after his contract was not renewed. (Editing by Matt Driskill and Mark Potter)